Submitted in response to CREG announcement: "Effects of Aging on Susceptibility to Carcinogenesis" - DCCP20: April 1, 1976. This project will examine the hypothesis that aging-associated alterations in extracellular regulators of target-tissue cell function lead to the development of a field of epigenetically altered cells which have an increased susceptibility to carcinogenesis. The experiment will correlate quantitative in vitro and in vivo biochemical evaluations of rat ventral and dorsolateral prostate cell function with histologic characterization of the tissues. Epigenetic regulation of cell function will be examined by quantitation of prostate content and isozyme distribution of lactic dehydrogenase, glucose-6-phosphate dehydrogenase, and acid phosphatase. Aspects of growth status and/or potential will be evaluated by quantitation of secreted polyamines. Androgen regulated membrane function will be characterized by quantitation of membrane prolactin receptor content. Basal acinar cell function will be characterized by quantitation of alkaline phosphatase. Aging-associated changes in androgen regulation of these parameters of prostate cell function will be evaluated in young mature, adult, and aged adult male AXC rats subsequent to androgen abalation or stimulation. The data will be analyzed for the interaction of age and treatment.